1. Field of the Invention
The invention concerns a process for improving the visibility in vehicles, in particular at night, poor weather and fog, wherein laser light in a wavelength outside the visible spectrum is emitted to a predetermined angle area, recorded via a camera, of which the images are then supplied to the vehicle operator.
2. Description of the Related Art
Poor visibility at night is a stressful and dangerous situation, and is feared by many drivers. The occurrence of accidents is significantly higher under poor visibility conditions than in the case of vehicle operation by day under good visibility conditions. In particular at night, the following difficulties occur:                The range of view is reduced in the case of low beams from on-coming traffic, and the range of view is underestimated by many vehicle operators. The leads to a late recognition of non-illuminated obstacles, pedestrians, bicycles without light and of animals, and therewith leads to accidents.        The vehicles operator is blinded for a short time by the headlights of oncoming vehicles and their reflection particularly in the case of wet road surfaces, so that in effect the vehicle operator is driving for a short period of time into a black hole. Particularly endangered are those with poor night vision and older vehicle operators due to their reduced vision capacity.        In the case of rain, fog and snowdrifts the range of vision can again be substantially reduced.        
An improvement of the view at night can be achieved by an opto-electronic system, as disclosed for example in DE 40 07 646 A1. The system records a video image of a traffic scene and presents this to the vehicle operator in suitable form. The presented image contains supplemental information, which the vehicle operator cannot see with his own eyes or can only recognize with difficulty, in particular at night, poor weather and fog.
In addition to the normal headlights this system supplementally contains infrared headlights, which utilize near infrared emitting laser diodes as light sources. The laser diodes are driven pulsed. A CCD-camera is incorporated in the roof of area of the vehicle for recording a video image. The CCD-camera has an electronic gate, which is synchronized with the laser diodes. An optical band pass filter is introduced in front of the camera lens. The video image is shown to the vehicle operator on a LCD-display.
The lasers emit in the near infrared at a wavelength of 810 nm. Since the infrared light is nearly invisible to the human eye and since the output of the utilized light is not higher than that of a conventional vehicle headlight, one has until now presumed that illumination can occur continuously, without endangering other vehicle operators.
Nevertheless it is desirable for purposes of improved safety to preclude any possibility of any conceivable danger to other vehicle operators.